. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 14.1.1. The COALESCE function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chapter 14. Converting to and from NULL 14.1. Substituting NULL with a value 14.1.1. The COALESCE function The COALESCE function in Firebird 1.5 and higher can convert NULL to most anything else. This enables (MyExpression is null) then” or similar constructions. The function signature is: COALESCE( Expr1, Expr2, Expr3, … ) COALESCE returns the value of the first non-NULL expression in the argument list. If all

supports a variety of optimizations such as, • Dynamically Switch Join Strategies • Dynamically Coalesce Shuffle Partitions • Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

supports a variety of optimizations such as, • Dynamically Switch Join Strategies • Dynamically Coalesce Shuffle Partitions • Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

which supports a variety of optimizations such as, Dynamically Switch Join Strategies Dynamically Coalesce Shuffle Partitions Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you turn when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

which supports a variety of optimizations such as, Dynamically Switch Join Strategies Dynamically Coalesce Shuffle Partitions Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you turn when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

supports a variety of optimizations such as, • Dynamically Switch Join Strategies • Dynamically Coalesce Shuffle Partitions • Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

supports a variety of optimizations such as, • Dynamically Switch Join Strategies • Dynamically Coalesce Shuffle Partitions • Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 8.9.1. COALESCE() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . rdb$types t on r.rdb$relation_type = t.rdb$type where t.rdb$field_name = 'RDB$RELATION_TYPE' and coalesce (r.rdb$system_flag, 0) = 0 The RDB$TYPE_NAME field will show PERSISTENT for a regular table, VIEW (GENERATOR) 8.9. Conditional Functions 8.9.1. COALESCE() Available in DSQL, PSQL Syntax COALESCE (, [, ... ]) Table 156. COALESCE Function Parameters Parameter Description exp1

supports a variety of optimizations such as, • Dynamically Switch Join Strategies • Dynamically Coalesce Shuffle Partitions • Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It

which supports a variety of optimizations such as, Dynamically Switch Join Strategies Dynamically Coalesce Shuffle Partitions Dynamically Handle Skew Joins In Kyuubi, we strongly recommended that you turn when the SortMerge Join transforms to BroadcastHash Join after applying the AQE rules. Dynamically Coalesce Shuffle Partitions Without this feature, Spark itself could be a small files maker sometimes, especially coalescePartitions.minPartitionNum to 1 in this case as Spark will try its best to but not guaranteed to coalesce partitions for output. How to set spark.sql.adaptive.coalescePartitions.initialPartitionNum? It